Resin containers, represented by polypropylene (PP) bottles or polyethylene terephthalate (PET) bottles (PET bottles), are used for accommodating various contents, such as drinks, makeup products, medicines, soaps, and shampoos. Such a container is generally formed into a predetermined shape by heating a resin preform, having a bottomed tube shape and formed by injection molding or the like, to a temperature that allows a stretching effect to be exhibited, and in this state, biaxial stretch blow molding using a blow molding device.
As for blow molding devices, one that uses a pressurized, incompressible fluid, such as a liquid, in place of pressurized air as the pressurized fluid for supplying into the preform is known. In this case, by using contents that are to be ultimately filled in the container as the product as the pressurized fluid, such as a drink, the process for filling the container with the contents can be omitted, and the production process thereof and the configuration of the blow molding device can be simplified.
For example, in Japanese Unexamined Patent Application Publication No. 2013-208834 is described a blow molding device provided with a mold for blow forming and into which a preform, which has been heated to a stretchable temperature, is mounted. A nozzle is inserted into the mouth part of the preform and a pressurized fluid supply part supplies a pressurized liquid into the preform via the nozzle. A stretching rod that is movable in the vertical direction, tretches the preform in the vertical direction (axial direction) while pressurized liquid is supplied into the preform to stretch the preform in the horizontal direction (radial direction), and the preform is molded into a container with a shape following the cavity of the mold.
With a conventional blow molding device such as that illustrated in the above mentioned Patent Application Publication, when the nozzle is raised after blow molding and separated from the mouth part of the container, liquid (incompressible fluid) adhered to the surface of the nozzle or the surface of the stretching rod can drip and fall downward. In particular, when using a liquid with relatively high viscosity such as shampoo or liquid soap as the incompressible fluid for performing blow molding, the time until liquid drips and falls from the nozzle and the like after blow molding is long, and further, because the liquid continues to drip for a while, as if to draw out a string of liquid, there are problems in that the liquid drips and falls onto the container after blow molding, or onto the mold after the container is pulled out, making these dirty.
In view of the foregoing, an object of the present invention is to provide a blow molding device that can prevent an incompressible fluid from dropping and falling from a nozzle and adhering to the container or mold after molding, when the nozzle is separated from the mouth part after blow molding.